[Objectives] A behavioral ethogram is a comprehensive catalog that encompasses the behaviors of a specific species or group of animals under investigation. Each species exhibits a unique behavioral ethogram, which aids in the systematic study of animal behaviors. The development of an animal behavior classification system within the realm of behavioral ecology facilitates researchers in conveniently examining relevant behaviors. By deconstructing the continuous variations in animal behavior into fundamental units, deeper insights into the complexities of these behaviors can be attained. The Tianshan Red Deer Cervus elaphus songaricus, recognized as a second-level national key protected wild animal and classified as endangered (EN) on the Red List of Chinese Vertebrates, has not been extensively studied in terms of its behavioral ethogram. [Methods] This study was conducted from July 2019 to September 2021 in Bogda Nature Reserve, Tianchi, Xinjiang, utilizing infrared camera monitoring technology to capture a total of 4 218 independently valid photographs and 881 videos of Tianshan Red Deer. Centering on ‘posture-movement-environment’, a behavioral classification coding system based on ecological functions was established to elucidate the behavioral ecology of the Tianshan Red Deer. In this system, the letters B, P, A, and E denote the behavioral set, gesture set, movement set, and environment set of the study species, respectively, while bi, pi, ai, and ei represent the elements or subsets of the sets B, P, A and E. The PAE coding classification is defined as follows: ; ; . This coding system is anchored in the ecological functions of the PAE framework. [Results] The research documented a total of 11 distinct postures (Table 1), 71 actions (Table 2), and 13 environment types (Table 3) observed in Tianshan Red Deer. By assigning PAE codes to the various environments, postures, and actions involved, a total of 75 behaviors were identified (Appendix 1), reflecting the species’ primary behavioral repertoire. [Conclusion] This study represents the first comprehensive construction of the behavioral spectrum and PAE coding system for Tianshan Red Deer. Notably, no image data was obtained for mating and parturition behaviors, likely due to the infrequency and brief duration of these events, as well as the deer’s preference for secluded locations, which minimises detection by infrared cameras. By establishing the behavioral ethogram and PAE coding system for Tianshan Red Deer, this research provides a scientific basis for their management and conservation efforts.